A U.S. college student detained in North Korea has confessed to his "severe" crime of stealing a political sign from a hotel there and has asked for forgiveness, the North's state media said Monday.

Otto Frederick Warmbier, a student at the University of Virginia, was questioned by North Korean officials after being caught committing, what the media there called, an anti-North Korea activity.

Warmbier said that on Jan. 1 he stole a political sign that had promoted "the Korean people's love for their system" from the hotel, according to the Korean Central News Agency.

"The aim of my task was to harm the motivation and work ethic of the Korean people. This was a very foolish aim," he said at a press conference in Pyongyang.

The state news agency earlier said that the student entered North Korea nominally for tourism, though his real intention was to undermine North Korea's unity.

Warmbier, 21, said he entered the North in late December via Beijing to commit the crime after being given such a task by the Friendship United Methodist Church, and with the U.S. government's approval.

He said a female church member asked him to bring back the sign as a "trophy" as doing so could "harm the unity and motivation of the North Korean people and show this country an insult from the West."

She promised to give him a used car worth US$10,000 if he succeeded and that her church would pay $200,000 to his mother if he were to be held captive by the North, the KCNA quoted him as saying.

Warmbier said his crime was "very severe and pre-planned."

"I apologize to the people and the government of the DPRK and beg for forgiveness," he said, referring to the acronym for the North's official name: the Democratic People's Republic of Korea.

(Yonhap)